UPC codes are unique product identifiers required for listing items on Walmart Marketplace. They help Walmart recognize your products and manage inventory accurately. Using valid UPC codes ensures your listings meet marketplace requirements and avoid rejection. Sellers need UPC codes to create new product listings, track sales, and maintain catalog consistency. To use, simply enter the UPC code while adding a product on Walmart Seller Center. Choosing reliable UPC codes helps ensure smooth product approval and better visibility across global marketplaces.